The present invention relates to an electrical test probe suitable for use in an electrical test of a plurality of semiconductor integrated circuits formed on a semiconductor wafer and a method for manufacturing the same.
A plurality of semiconductor integrated circuits formed on a semiconductor wafer generally undergo an electrical test before being separated into respective chips to determine whether or not they are manufactured in accordance with the specification. In this electrical test, a probe assembly comprising electrical test probes to be connected to electrodes of devices under test that are the respective semiconductor integrated circuits is used. The devices under test are connected to a tester via this probe assembly.
One of the conventional probes used for this probe assembly is one comprising a plate-shaped probe main body section and a probe tip section provided on the probe main body section and that is to abut on an electrode of a device under test (for example, refer to Patent Document 1). The probe main body section has an attachment portion to a probe board, a pair of arm portions extending from the attachment portion to the lower side of the probe board laterally along the probe board with a space from the probe board, and a pedestal portion formed integrally with the arm portions so as to combine the ends of the both arm portions, and the aforementioned probe tip section is provided on the pedestal portion. In Patent Document 1, it is proposed that the probe main body section should be made of a highly tough conductive material, and the probe tip section provided at the lower end of the pedestal portion of the probe main body section should be made of a metal material with excellent hardness.
By forming the probe main body section by the highly tough metal material, the probe tip section can be made to slide on the electrode along with elastic deformation of the arm portions of the probe main body section when the probe tip section of the probe is thrust to the electrode of the device under test. This slide of the probe tip enables oxide films on the electrode to be scraped away. Thus, by letting an overdriving force that causes the aforementioned elastic deformation act on the arm portions of the probe, the oxide films of the electrode are removed by the probe tip of the aforementioned probe tip section, and reliable electrical contact between them is obtained. Also, by forming this probe tip section by the highly hard material, abrasion of the probe tip caused by the slide is suppressed.
Meanwhile, such a probe is microscopic. Thus, in manufacturing the probe, a photolithographic technique adopted in the semiconductor manufacturing technique is utilized. Specifically, a resist pattern having openings corresponding to the probe tip section and the probe main body section is formed on a base table with a photosensitive photoresist, and respective metal materials are selectively deposited in the respective openings for the probe tip section and the probe main body section, thus to form a probe. Also, the probe tip section is formed with its base portion buried in the probe main body section. When the probe tip of the probe or the tip end of the probe tip section is thrust to the device under test, an acting force such as bending or shearing concentrates on the base portion of the probe tip section in a lateral direction parallel to the sliding direction as a result of the aforementioned slide of the probe tip. When the stress on the base portion increases by the concentration of the acting force on the base portion, deterioration of the probe tip section at its base portion will be accelerated.
In an attempt to decrease the stress on the base portion of the probe tip section, the flat surface shape of the opening of the resist pattern for formation of the probe tip section is formed in a tapered shape so as to be broadened toward the end surface of the base portion, and thus the cross-sectional shape of the probe tip section at its base portion is broadened toward the end surface of the base portion coupled with the probe main body section.
However, in the conventional case, the thickness in the Y direction, which is a direction of depositing the metal material for the probe tip section as seen on a flat surface perpendicular to the protruding direction of the probe tip section, is uniform, as described above. Increase of the cross-sectional area of the base portion is attempted only by increase of the width dimension along the X direction perpendicular to the Y direction as seen on the aforementioned flat surface. Such increase of the dimension is restricted along with miniaturization of ICs.
Accordingly, it has been desired to attempt to improve durability of the probe by further improvement of durability of the probe tip section and further decrease of stress.
[Patent Document 1] International Publication WO2006/075408 Pamphlet